That's kind of a loaded word. It means different things to different people. And honestly, it means different things to ME at different times. My husband and I have been married for over 17 years. And depending on the day, marriage is WONDERFUL. On other days, not so much! ;-) I remember before we got married, Ryan's Grandpa told me one thing. He said, 'people will tell you that marriage is 50/50. But that's not true. It's actually 90/10. Most days you will think that YOU'RE giving 90% and he's only giving 10%, and he'll think HE'S the one giving 90% and you're only giving 10%.' It's probably the best piece of advice anyone has ever given me. And it's SO true. Most days I DO feel like I'm giving 90%, but I'm sure that he feels the same way.
No one ever said marriage is easy. And if someone DOES tell you that, then they're lying. Another piece of advice I got, from my mom, is that you can't live with someone 24/7 and NOT have problems. You're not the same people. You don't have the same thoughts and feelings, so you're going to have some problems. But making a marriage work means working THROUGH those problems. It means knowing that some days are good days, and some days are bad days. And hopefully, there's a lot more good days than there are bad days.